Patch msdosfs.kext Info.plist for add OSBundleRequired="Console". That provides access to an EFI partition in single user mode (disabled for 10.10 and up);

Update a records about the unsigned installed kexts in the AppleKextExcludeList.kext (disabled for 10.10 and up);

Pack kext files to mkext cache file;

UnPack mkext cache files.

Note:
The latest KU uses highly modified high-speed method of repair kexts. To all kexts granted the same rights (a little more liberal, than it is necessary). This saves a lot of time and nervous when installing and configuring the MAC OS X. On the system performance, is not affected. After installing and configuring the system, if there is free time, run "Disk Utility", and repair the kexts, according to their native permissions.

Unfortunately, "kext-dev-mode=1" and "rootless=0", these keys are no longer working for future versions of Mac OS X starting with El Capitan GM. You need disable SIP with Clover Bootloader.

To open an unsigned application:

just right-click the app and select Open or (global setting) run in terminal this command:

sudo spctl --master-disable

Some thoughts on the repairing of the kexts permissions:

Spoiler

I want to share my thoughts on the repairing of the kexts permissions:
From time to time you can hear the opinion that after the use of Kext Utility will still need to repair the kexts in Disk Utility, then why do you need to use KU?
And it may be easier to type in the terminal well-known commands: